Furnace.



D. R. KEITH.

FURNACE.

.APPLIGATION FILED FEB. 25. 1914.

Patented D50. 15, 1914.

3 SKEETS-SHEET l.

D. R. KEITH.

FURNACE.

APPLICATION FILED FEB. 25, 1914. 1 1 21 ,508. Patented Dec. 15, 1914.

3 SHEETS-SHEET 2.

2/ l Z o o 0 O Z J ii;

D. R. KEITH.

FURNACE.

APPLICATION FILED Emma, 1914.

1, l 21 ,508. fitented Des. 15, 1mg,

3 SHEETS-SHEET 3 M 7, 4 'rnllulllln swan/wive- Mai am imme/wee DAVID B. KEITH, OF FORT SCOTT, KANSAS.

FURNACE.

Specification of Letters Patent.

Patented Dec; 15, 1914.

Application filed February 25, 1914. semi Io. 821,049.

To all whom it ma concern: 1 Be it known t at I, DAVID R. KEITH, a citizen of the United States, residing at Fort Scott, in the county of Bourbon and 5 State of Kansas, have invented new and useful Improvements in Furnaces, of

the following is a specification.

This invention relates to improvements in furnaces, especially force draft furnaces and with reference to the provision of improved,

means for promotingcombustion of -3the gases generated in the fire box so as to increase the heatin capacit of a furnace and consume the smo e, one o ject of the inven- 16 tion being to efiect improvements inthe construction of the bridge wall so as to cause the gases passing from the fire box to be {superheated and consumed; another object being to provide improved means for intro- 20 dueing air in at the bridge wall and at-the rear of the fire box and above the bed of fuel therein and to heat such air sons-to cause it to readily unite with the gases and render the latter combustible; another ob-flject being to provide improved means for automatically cutting off the supply of air to the ash pit and under the grate bars while the furnace door is open, as when stoking the furnace, another object being to provide improved means for regulating the supply of superheated air to the rear portion of the fire box. I

- The invention consists inthe construction,

combination and arrangement of devices 85 hereinafter described and claimed.

In the accompanying drawings :Figure 1 is a front elevation of a furnace constructedin accordance with my invention. Fig. 2

is a detail sectional view on the plane indimated by the line aa, of Fig. 3. Fig. 3 is a vertical longitudinal sectional view of the furnace on the plane indicated by the line i 6-15 of Fig. 1. Fig. 4 is a vertical transverse sectional view of the same on the plane indicated by the line cc of Fig. 3. Fig. 5 is a detail horizontal sectional view -on the plane indicated by the line d-d of Fig. 3 and showin ment of ba e piers on the bridge wall. Fig.

60 6 is a detail longitudinal sectional view of the pipe which supplies heated air. to the rear portion of the firebox and of the tubular valve which regulates the intake of air which:

the construction and arrangeby said pipe. .Fig. 7 is a detail elevation of thevalve o crating devices, with, the front furnace wa .partly in section. The furnace here shown for the purposesv ofthis specification is a boiler heatingfurnace but the furnace may within the scope of my invention be of any suitable construc- 'tion and'usedforany-purpose." The boilerf;

is indicated atl, the furnace side walls are 'indicatedat 2, the front wall at 3, the bridge wall at-4,.thci fsh pit at 5, the fire box at 6,

and the grate -"bars at 7. Preferably the.65 v

grate barsare. of the hollow force draft type but may withinthe scope of my invention be of any suitable construction. In rear of the fire box is a secondary combustion chamber 8 in which such gases as escape combustion. in the fire box are consumed. The ash pit 'doors. are indicated at 9 and the fuel doors ln-accordance with my invention I provide an air supply duct 11 which is here shown as having a horizontally, arranged forwardly extending lower intake arm 12 and a vertical. uptake arm 13, the said uptake arm being. arranged in a recessin the wall 3 and having an opening l l on its rear side at its upper end for discharging air directly into the ash pit .5 and under the grate bars to supply fuelon the grate. bars and in the fire box or combustion chamber with the air necessary to cause the fuel to burn. I also provide an oxygenating duct to supply air to the fire box at a point above the bed of fuel and at the rear end of the fire box to render such gases as would otherwise escape combustion in the fire box or combustion chamber combustible and insure their ignition and consumption in the furnace and thus increase the heating capacity of the furnace, effect an economy in fuel and prevent the furnace from discharging .95 smoke. This oxygenating duct is here shown as comprising an air supply pipe 15,

a retort chamber 16 and a discharge block 17. The retort chamber is constructed in the bridge walls and comprises a lower horizontal intake, arm 18 and a vertical uptake arm 19. The discharge block 17 is made of refractory material and is built in the front side of the bridge wall at a point to .the rear and at a suitable distance above the 105 grate bars and is provided with a series of fiie box to form a rearwardly contracting throat passage 22 under the boiler 1 and between the fire box or combustion chamber 6 and the secondary combustion chamber 8 and in this throat is arranged a series of battle piers 23-24; which are built on the top of the bridge wall and are preferably constructed of fire brick or other suitable re-.

fractory material. The front'baifie piers 23 are spaced apart and the rear baffle piers 21 are arranged in line with the centers of the spaces between the front bafiie piers so that the said baflle piers 23-24 are arranged in staggered relation so that gases passing rearwardly from the fire box through the throat 22am deflected and given a tortuous course by the said baffle 'piers' thus causing the gases to be thoroughly mixed and the said bafile piers being highly heated to cause said gases tends through to be also superheated so that they become consumed in the secondary cha'mber; The airwhich is supplied to'the rear portion of the fire box, above the bed of fuel'through the oxygenating duct is also highly heated during its passage through the retort chamber 16 andthe block 17 and such,highly heated air being discharged into the gases in the combustion chamber of the fire box 6 becomes mingled with the gases and renders them highly combustible. Hence the gases arising partially in the fire box and finally in the secondary combustion chamber, thus utilizing the fuel to the fullest extent effecting an economy in the fuel and preventing smoke.

The air supply pipe 15 which constitutes an element ofthe oxygenating duct is arranged longitudinally in the fire ibox, ex-

the uptake 13 of the air duct 11 and also through the front wall 3 of the chamber and has a bearing in the front u all, also has bearings in the uptake of the air duct 11 and the rear portion of said pipe, which extendsinto the arm 18 of the retort chamber 16 has a bearing as at 25 in a plate 26 which closes the front end of said intake arm 18 of the retort chamber. This plate has air inlet openings 27 '27 which lead di-. rectly from the rear end of the ash pit 5. The pipe 15 is provided atits front end with a crank arm 28 by means of which it may be turned or oscillated in its bearings and the' said pipe is also provided near its rear end, with a shutter valve 29 which projects from the said pipe 15, at right angles from the heated fuel-are consumed,'

the opening 27 according to the direction in which said pipe 15 is turned.

A damper 30 is secured to the pipe 15 to be turned therewith and is arranged in the uptake of the air supply duct 11. This dam per is arranged at right angles to the shutter valve 29 so that when the damper is in horizontal position to close the uptake of the air duct 11 and cut oi the supply of air to the ash pit, the shutter valve 29 is in position to close the opening 27 thereby" cutting off the supply of air to the retort 'chamber 16 through the opening. 27 and from the ash pit. i i

In the pipe 15 is a tubular valve 31 which is arranged to be partly turned in said pipe ,15 and 1s closed at its front end as at 32.

The pipe 15 has an air intake opening 33 in I i the uptake of the air duct 11 and on the side opposite the damper 30. The tubular valve 31 has a similar opening 3 1 which may be turned into and out of registry with the opening 33. Said opening extends about halfway across the pipe 15, and 31. At the front end of the tubular valve 31 is an arm 36 which projects therefrom at right angles thereto and is arranged on the front side of V front wall A guide projects frQm said wall and an operating rod 36* travels in said guide and is attached to the arm 36 and may be used for partly turning the tubular valve. The tubular valve being connected by the pipe 15 turns with said pipe and is also adapted to be turned independently thereof so that the opening 33 may be closed by the valve 31 whenever this is desired. At

the rear end of the tubular valve is .a shutter valve 35 foruncovering or closing the open ing 27. a

Each fire do0r.10 is provided with a tappetarm 38. A horizontallyarranged shaft 39 which is parallel with the front wall 3 and arranged at a suitable distance above thefire doors is mounted in bearings 40 with which ,a bracket 41 vis provided, the said bracket being secured on the front side of a the wall 3. This shaft 39 is provided near its ends with rock arms 12 which may be moved into and out of engagement with the tappet arms of the fire door. The said shaft also has a lever 1 1 by means of which it can be turned and the said lever is connected by .a rod 45 to a link 15 that operates in guides 45h A rod 45 connects said link ,to the arm 28 of the pipe 15.

ings 3334 are also in registry. This al-' 0 When the fire doors are closed the damper 30 is in open position and the shutter valves lows air to pass outrabove thefuel bed and into direct contact with the smoke. return-f ing it over the fuel bed and causing the smoke to be consumed. When the rod 36 is moved downwardly through about one V while stoln'ng.

half the extent of the limit of its movement,v

the tubular valve 31 will be turned sufii- :iently to cause the opening"33 in the pipe to be closed but not to a sufficient extent to cause the opening 27 to be closed by the shutter valve 35. When said rod is moved downwardly to the full extent the said opening 27 will be closed by the shutter valve 35, the opening 33 remaining closed but the damper 80 and the shutter valve 29 will remain in open position. When a fire door is opened the lever 4-1 will be automatically turned and through its connections 45 and i5 and the arm 28 will partly turn the tube 15, thus closing the damper 30 and also closing the opening 27 by the shutter valve 29. This cuts off the supply of air to the-fire This movement of the pipe 15 however, will cause its opening 33 to register with the opening 34 of the tubular valve and hence air will be supplied to the fire, above the grate, through said tubular valve and the chamber 16 as-Will be under.

stood. .VVhen the door is closed the pipe 15 in turning the opening 27 will cause the tubular valve to turn therewith and the ports iii-35 and 27 will be open to supply air to the chamber-16'. When thus arranged the furnace is in maximum operating condition. \Vhen it is desired to check the fire the rod 36 can be operated to partly turn the tubular valve to cause the shutter valve 37 to close the opening 27 and to also cause the tubular valve to close the opening 27. The lever 44: may be manually operated to turn the'pipe 15 and hence cause the damper 30 to be moved to closed position while the openings iii-34 will register and thus admit air to the chamber 16. The closing of the damper 30 when thefuel doors are open prevents an excessive amount of cold air from entering through the fuel door owing to the check on the draft occasioned by such closing of the damper.

Air supplied from below the grate bars through the air duct 11 and the ash pit, in connection with the air supplied to the rear end of the fire box above the bed of fuel through the oxygenating duct, causes the unconsumed gases which arise from the fire immediately after the latter has been supplied with fuel to become commingled with the superheated air supplied by the oxygenating duct, and as the mixture passes over the bridge wall and between the bafile and superheated piers it will be ignited in the combustion chamber thus preventing smoke and causing the gases to give out their caloric.

Having thus described my invention, I claim:

1. A furnace having a fire box, a grate therefor, an ash pit, an air duct discharging into the ash pit, an oxygenating duct connecting the air duct and the rear portion of the-firebox, at a point above thegrate,

said oxygenating duct including a tubular element mounted for oscillatory movement and extending into the air duct, a damper'" for the air duct carried by and movable". with said tubular element and means to; turn said tubular element and said damper;

to control the intake of air through the duct.

2. A furnace having a fire box, a grate therefor, an ash pit, an air duct discharging into the ash pit, an oxygenating duct connecting the air duct and the rear portion of the fire box, at a point above the grate, said oxygenating duct including a tubular element mounted for oscillatory movement and extending into the air duct, a damper for the air duct carried by and movable .with said tubular element and means to of the firebox, at a point above the grate,

said oxygenating duct including a tubular. element mounted 1 for oscillatory movement and extending into the air. duct, a damper for the air duct carried by and movable with said tubular element and means to turn said tubular element and said damper, and a valve also operatedby said tubular element to open or 010% and cut ofi communication getween the ashpit and said oxygenating uct.

4. A furnace having a firebox, a grate therefor, an ash pit, an air duct discharging into the ash pit, an oxygenating duct connecting the air duct and the rear portion of the fire box, at a point above the grate, said oxygenating duct including a tubular element mounted for oscillatory movement and extending into the air duct, a dam er for the air duct carried by and movab c with said tubular element and means to turn said tubular element and said damper, and a valve also operated by said tubular element to open or close and cut off communication between the ash pit and said oxygenating duct, a fire door and means operated by the fire door to actuate said tubular element and said damper.

5. A furnace having a fire box, a grate therefor, an ash pit, an air duct discharging into the ash pit, an oxygenating duct connecting the air duct and the rear portion of the fire box, at a point above the rate, said oxygenatin duct including a tu ular element mounted for oscillatory movement and extending into the air duct, a damper for the air duct carried by and movable with said tubular element and means to turn said tubular element and said damper, and a valve also operated by said tubular element to open and cut off communication between the ash pit and said oxygenating duct, a fire door and means operated by the fire door to actuate said tubular element and said damper and valve.

' 6. A furnace of the class described having a fire box, a grate therefor, an ash pit below the grate, an air duct dischargin into the ash pit, an oxygenating duct leadi the air duct to the rear portion of the fire box at a point above the rate and including a tubular element extending across the air duct and mounted for oscillatory movement, said tubular element having an air inlet opening arranged in said air duct, a damper for the air duct carried by and movable with said tubular element, means to turn said tubular element, a valve to open and close the air intake opening of said tubular element and means to operate said valve.

7. A furnace of the class described having a fire box, a grate therefor, an ash pit below the rate, an air duct discharging into the ash pit, an oxygenating duct leading from the air-duct to the rear portion'of the fire box at a point above the grate and includinga tubular element extending -across the, air duct and mounted for. oscillatory movement, said tubular element having anair inlet opening arran ed in said air duct, a damper for the air uct carried by and movable with said tubul'arelement, means to turn said tubular element, a valve to open and close the air intake opening of said tubular element and means to operate said valve.

8. A furnace of the class ing a fire box, a grate therefor, an ash pit below the grate, an air duct discharging ng from described having from the air duct to the rear portion of the fire box at a point above the grate and including a bypass leading thereto from the ash pit and also including a tubular element extending across the air duct and mounted for oscillatory movement, said tubular element also having an air inlet opening arranged in said air duct, a damper for the air duct carried by and movable with the tubular element, means to turn said tubular element, a valve to open and close the air intake opening of said tubular element and means o erated by said-valve to open .and close sai bypass.

9. A furnace of the-class described having the grate, an air duct discharging into the ash pit, an oxygenating duct leading from the air duct tothe rear portion of the fire box, at a point above the grate and includingapair of bypasses leading thereto from the ash pit, said oxygenatingduct also including a tubular element extending across the air duct and mounted for oscillatory movement, said tubular element having a valve to -0 en and close-one of said bypasses and also aving an air intake opening arranged -in said air duct, a damper for the airduct carried by and movable with the tubular element, means to turn said tubular element, a tubular valve to openand close the air intake opening of said tubular elementand arranged for oscillatory move- DAVID n. KEITH.

-- Witnesses:

J. R. NEWMAN,

C. A. VANKnLzER. 

